Multimodal automated fabrication with concrete: Case study and structural performance of ribbed CFRP-reinforced concrete ceilings

A significant amount of concrete in building construction can be conserved by implementing ribbed concrete ceilings. However, their fabrication remains challenging due to the extensive manual labor required for formwork production. This paper introduces a modular ribbed ceiling system that integrates topology-optimized design principles with advanced digital manufacturing techniques. The system consists of two key components: a point-supported slab-column connection module (SCCM) and an inter-column support strip module (SSM). To enable efficient production, an innovative multimodal automated fabrication approach is presented, combining robotic casting with 3D concrete printing and reinforcement integration. In this method, slender, bi-directionally oriented ribs are 3D printed onto a robotically pre-cast concrete plate, with protruding CFRP reinforcement guiding rib placement. This process enables the production of freeform, material-efficient ceilings with high geometric flexibility. Structural tests, including bending, shear, and punching shear assessments, were conducted to evaluate the load-bearing behavior of the system. The study demonstrates the feasibility of automated multimodal manufacturing techniques for producing optimized ribbed CFRP-reinforced concrete structures, paving the way for more sustainable and resource-efficient construction.